Artemis

In continued preparations for the Artemis I wet dress rehearsal  test, with tanking targeted for Monday, teams encountered an issue maintaining helium purge pressure on the upper stage engine after change-out of a regulator on the mobile launcher. The RL10 engine on the upper stage uses helium to purge the engine and also to activate upper stage valves during wet dress rehearsal operations. After initial troubleshooting, the team reestablished normal helium purge, and is continuing work to determine the cause of a restriction in the helium flow. Engineers will conduct troubleshooting tomorrow to confirm and characterize system performance. If needed, the mission management team will meet Sunday to disposition any adjustments in the procedures or modifications in test objectives as necessary. After the wet dress rehearsal test, SLS and Orion will return to the Vehicle Assembly Building, and engineers will conduct additional inspections of the related flight systems to further evaluate system performance. The Space Launch System rocket, the Orion spacecraft, and the supporting ground system elements remain in stable condition.

The countdown for the two-day test is currently slated to begin with call to stations beginning at 5 pm EDT on Saturday, April 9 with T-0 planned for 2:40 pm on Monday, April 11. While engineers investigate the issue, teams continue to refine the test schedule to account for insights gained during the previous runs and activities, or test objectives, that were completed earlier this week and no longer need to be included in the next test run, such as configuring ground support equipment. Pending additional analysis, NASA expects to have a forward plan tomorrow for wet dress rehearsal testing.

Check back at this blog for an update on wet dress rehearsal testing for the Artemis I mission. NASA is streaming live video of the rocket and spacecraft on the Kennedy Newsroom YouTube channel. Real-time updates will be provided on the Exploration Ground Systems Twitter account with “go” for tanking.

Teams are preparing for the next attempt of the Artemis I  wet dress rehearsal, pending range availability and restoration of propellants and gases during the test. Through the past two test runs April 3 and 4, engineers accomplished several test objectives that will prepare the teams and integrated systems for launch:

• • Configuring Launch Pad 39B and the mobile launcher for the test, just as it will have to be prepared for launch
  • Clearing personnel and equipment from the launch pad after configuration in order to proceed with propellant loading
  • Powering up Orion and the SLS rocket systems in launch configuration, including the solid rocket boosters, the core stage, and the interim cryogenic propulsion stage
  • Checking out and verifying the Orion spacecraft countdown and commanding by flight controllers at NASA Johnson Space Flight in Houston
  • Checking out the guidance, navigation and control system and all the integrated software that operates across the rocket, Orion, ground systems and ground support centers including the Launch Control Center
  • Verifying and checking out all the range safety and systems with the range
  • Draining the liquid oxygen and liquid hydrogen after the test
  • Powering down the rocket, the spacecraft and ground systems and putting them in a safe configuration

All these activities are necessary for a successful launch or in the event launch controllers decide not to proceed with launch if a technical or weather issue arises during or prior to the countdown. Completing these objectives will allow the team to use the next test opportunity to focus on executing the remaining objectives during dynamic operations, such as loading the cryogenic propellant and working through the launch countdown.

Inspections after the second test showed the vent valve that prohibited the team from proceeding with loading liquid hydrogen was configured physically in a closed position, which prevented it from being commanded remotely to an open position. The valve positioning has since been corrected.

Teams were also able to demonstrate their ability to work through several issues, such as severe weather, delays in getting a gaseous nitrogen supply source provided by a commercial vendor up and running, and fixing systems like fans that did not perform as expected.

NASA’s Space Launch System (SLS) rocket, the Orion spacecraft, and the supporting ground system elements are all in excellent condition and in a configuration that supports the next opportunity.

Listen to a replay of the latest briefing, and check back at this blog for an update on the targeted date for resuming WDR testing for the Artemis I mission.

The Artemis I team has ended today’s attempt at the wet dress rehearsal test at 5 p.m. The countdown ended after partially loading liquid oxygen into the Space Launch System core stage tank. This provided the teams a valuable opportunity for training and to make sure modeled loading procedures were accurate. This was the first time using new systems at NASA’s Kennedy Space Center Launch Complex 39B. The team was able to monitor the Artemis I core stage as it was exposed to cryogenic liquids and gather data that will inform updates to propellant loading procedures.

After troubleshooting a temperature limit issue for the liquid oxygen, which delayed the countdown by several hours, the team successfully developed a new procedure for loading the liquid oxygen and filled the tank to 50 percent. Liquid oxygen is an extremely cold, or cryogenic, propellant that is maintained at minus 297 degrees Fahrenheit.

During chilldown of the lines in preparation for loading the liquid hydrogen, the teams encountered an issue with a panel on the mobile launcher that controls the core stage vent valve. The purpose of the vent valve is to relieve pressure from the core stage during tanking. Given the time to resolve the issue as teams were nearing the end of their shifts, the launch director made the call to stop the test for the day. A crew will investigate the issue at the pad, and the team will review range availability and the time needed to turn systems around before making a determination on the path forward.

The wet dress rehearsal is the last major test before launch. This test allows the team to practice propellant loading and thoroughly check out the Artemis I rocket systems as they are exposed to cryogenics.

NASA is targeting Monday, April 4, to resume the Artemis I wet dress rehearsal test. The test was stopped Sunday, April 3 prior to tanking due to loss of ability to pressurize the mobile launcher using two fans. The fans are needed to provide positive pressure to the enclosed areas within the mobile launcher and keep out hazardous gases. Without this capability, technicians were unable to safely proceed with remotely loading the propellants into the rocket’s core stage and interim cryogenic propulsion stage.

The launch control team will meet at 6 a.m. EDT and review the status of the operations before deciding if they will proceed with propellant loading. The targeted test T-0 is planned for 2:40 p.m. EDT. Meteorologists with the U.S. Space Force Space Launch Delta 45 currently predict favorable weather conditions for tanking operations.

During a teleconference this evening, Mike Sarafin, Artemis I mission manager and Charlie Blackwell-Thompson, Artemis launch director indicated that teams are continuing to troubleshoot the issue with the fans and aim to have a resolution later tonight. NASA will provide an update the morning of April 4, prior to the tanking meeting.

The Space Launch System (SLS) core stage, interim cryogenic propulsion stage, and Orion spacecraft will remain powered up overnight. The SLS boosters will be powered down, and then powered up again Sunday morning. Teams will work through the night and into the morning to complete necessary preparations ahead of loading propellants into the rocket.

NASA is streaming live video of the rocket and spacecraft at the launch pad on the Kennedy Newsroom YouTube channel.

Teams have decided to scrub tanking operations for the wet dress rehearsal due to loss of ability to pressurize the mobile launcher. The fans are needed to provide positive pressure to the enclosed areas within the mobile launcher and keep out hazardous gases. Technicians are unable to safely proceed with loading the propellants into the rocket’s core stage and interim cryogenic propulsion stage without this capability.

Teams will now meet to determine next steps and establish a go forward plan. The next opportunity to proceed into tanking is Monday, April 4. Teams will discuss range and commodity availability as part of the forward plan.

At approximately 6:45 a.m. EDT, the launch director and mission management team chair gave the “go” to begin tanking the rocket. Meteorologists with Space Launch Delta 45 said there were no weather violations for the test. All elements are powered up and teams have moved the side flame deflectors into position and completed final preparations and closeouts of the umbilicals that connect the mobile launcher to the Space Launch System rocket and Orion spacecraft.

The flame deflectors divert ignited propellant away from the rocket and ground infrastructure at liftoff. Although the engines will not be lit during the test, launch controllers are using the wet dress rehearsal to practice countdown milestones like they would on launch day.

The umbilicals provide power, communications, coolant, and fuel to different parts of the rocket. Additional accessories provide access and stabilize the rocket and spacecraft. During launch, each umbilical releases from its connection point, allowing the rocket and spacecraft to lift off safely from the launch pad.

Cryogenic loading operations are schedule to begin around 7:20 a.m., or with L-7 hours, 20 minutes remaining in the countdown.

Once propellant loading operations begin, liquid oxygen (LOX) and liquid hydrogen (LH2) will flow into the into the rocket’s core stage and interim cryogenic propulsion stage tanks and be topped off and replenished as some of cryogenic propellant boils off. The team will also conduct leak checks to ensure propellant loading is proceeding as expected.

NASA is streaming live video of the rocket and spacecraft at the launch pad on the Kennedy Newsroom YouTube channel. Venting may be visible during tanking operations. NASA is also sharing live updates on the Exploration Ground Systems Twitter account.

The next blog update will be provided when core stage propellant loading is underway.

The Artemis I launch team continues to press ahead through the wet dress rehearsal countdown. During the overnight hours after determining four lightning strikes at Launch Pad 39B would not stop the countdown from continuing,  the interim cryogenic propulsion stage (ICPS) and solid rocket boosters of the Space Launch System rocket were powered up. Shortly after, all non-essential personnel left the launch pad.

Teams continue to prepare to load super-cooled liquid hydrogen and liquid oxygen into the Space Launch System core stage as part of the Artemis I test, which began on April 1.

At 6 a.m. EDT, or L-8 hours, 40 minutes, the launch team reached a planned 1 hour, 30-minute built-in hold in the countdown. During this time the mission management team will make a “go” or “no-go” decision to proceed with tanking operations. If mission mangers elect to proceed with cryogenic loading operations, it is scheduled to begin at L-7 hours 40 minutes.

Tanking milestones include filling the rocket’s core stage and ICPS tanks with over 700,000 gallons of liquid oxygen and liquid hydrogen. This will occur over a series of different propellant loading milestones to fill, top off, and replenish the tanks.

NASA is streaming live video of the rocket and spacecraft at the launch pad on the Kennedy Newsroom YouTube channel. NASA is also sharing live updates on the Exploration Ground Systems Twitter account.

The next blog update will be provided after the “go” or “no-go” decision to proceed with tanking operations.

Engineers confirmed there were four lightning strikes to the lightning towers within the perimeter of Launch Pad 39B. Teams have determined the first three were low intensity strikes to tower two and are continuing to review data from the fourth strike, which was higher in intensity to tower one. At the time of the strikes, Orion and the Space Launch System (SLS) core stage were powered up and the solid rocket boosters and interim cryogenic propulsion stage (ICPS) were not. Teams currently see no constraints to proceeding with the test countdown timeline as planned and will continue procedures to power up the SLS boosters and ICPS overnight.

Overnight, engineers will also work to make up time for activities that were paused due to the severe weather. The Mission Management Team will review the schedule and data from the power ups and sensors at the pad at a 6 a.m. EDT tanking meeting before making the decision to proceed with the test.